Six Flags (PKS:NYSE - commentary - research - Cramer's Take) said its board unanimously decided to seek proposals for a possible sale of the company, a move that comes after Washington Redskins owner Dan Snyder said he wants to raise his stake in the theme-park operator and become chairman.

Shares of Six Flags were rising 96 cents, or 15%, to $7.50 in premarket trading.

On Thursday, Six Flags said it "intends to pursue a prompt and orderly auction process," and will invite Red Zone LLC, the investment vehicle controlled by Snyder, to participate, "should Mr. Snyder have a serious interest in pursuing an acquisition of the entire company."

The company also added that whether "Red Zone participates in our auction process, we certainly hope it will not take any action that would impede our ability to maximize value for all stockholders."